This invention relates to profile-wrap articles in which the profile and the wrap are bonded using moisture-reactive hot-melt adhesive compositions; to moisture-reactive hot-melt adhesive compositions useful for making profile-wrap articles; and to a method of making such profile wrap articles.
Some moisture-reactive hot-melt polymer compositions are useful as reactive hot-melt adhesives for bonding profile-wrap articles. Desirable properties of such adhesives include high green strength, high ultimate strength, and short open time. Green strength is the bond strength prior to completion of the reaction with moisture; ultimate strength is the adhesive strength after the reaction with moisture is essentially complete; and open time is the period of time after the hot-melt adhesive is applied to one or more substrates, during which one or more subsequent substrates may be contacted with the adhesive, without significant loss of ultimate strength.
U.S. Pat. No. 6,303,731 describes a pressure-sensitive adhesive (PSA) and suggests that the PSA could be used in profile wrapping. By definition, PSA's are tacky and remain so indefinitely. Additionally, PSA's generally have relatively low ultimate strength when used to bond articles.
The problem therefore faced by the inventor is the provision of a moisture-reactive hot-melt adhesive composition that achieves a desirably short open time, usefully high green strength, and desirably high ultimate strength. The inventor has found that the desired properties can be achieved by the provision of a moisture-reactive hot-melt urethane composition that is not a pressure-sensitive adhesive and that incorporates at least one non-reactive acrylic polymer and that excludes effective amounts of reactive acrylic polymer. The inventor has further found that the moisture-reactive hot-melt urethane composition is useful for bonding profile-wrap articles.